1. Field of the Invention
The present invention relates to a cable modem module which serves as an interface with a network using a cable television (CATV) line, for example. The present invention also relates to a transmitter-receiver which makes data communications with the network via such a cable modem module as described above.
2. Description of the Related Art
As is well known, a cable modem device has been developed as an interface which connects a transmitter-receiver, such as a personal computer (PC), owned by a user to a network using a CATV line, for example. Such a cable modem device has been manufactured, separately from transmitter-receivers, as stand-alone equipment that a user can handle directly.
In general, the cable modem device is equipped on its back with a radio-frequency (RF) coaxial connector for connection to a CATV trunk line, an Ethernet connector or jack for connection to a PC or the like, a universal serial bus (USB) connector or jack, a reset switch to return the modem to its initial state, and a power supply connector to receive electric power.
The cable modem device is equipped on its front with a display unit, consisting of light emitting diodes or liquid crystal elements, which indicates whether electric power is supplied, whether connection with the CATV center station has been set up, whether connection with the PC has been set up, and the states of other functions, a power switch, and so on.
The cable modem device is housed in a case made of a synthetic resin material and has its shape determined according to whether it is to be placed in the neighborhood of a PC or to be hung on a wall.
Recent large-scale integration of semiconductor chips and enhanced performance and high-density packaging of parts have promoted cost reduction and size reduction of cable modem devices. In terms of size, therefore, it has become possible to incorporate a cable modem device into a transmitter-receiver.
However, since the cable modem device is originally constructed separately from the transmitter-receiver, incorporation of the cable modem device into the transmitter-receiver will require improvements in several respects.
Japanese Unexamined Patent Publication No. 2002-16524 discloses a transmission/reception radio-frequency device which has a transmitting-system block and a receiving-system block built into one case. However, this publication does not describe incorporation of the case with the built-in receiving-system and transmitting-system blocks into a transmitter-receiver.